Posted
by
CmdrTaco
on Tuesday December 07, 2010 @05:00PM
from the i-burnt-my-fingers dept.

Arvisp writes "As predicted, the a 'mega-filament' of solar magnetism erupted on Dec. 6th, producing a blast of epic proportions. NASA's Solar Dynamics Observatory recorded the action as the 700,000-km long structure lifted off the stellar surface and--snap!!--hurled itself into space. The eruption produced a bright coronal mass ejection (CME) observed by the STEREO-A spacecraft: video. Earth was not in the line of fire; the cloud should sail wide of our planet. Earth-effects might be limited to pretty pictures."

These things aren't mysteries, even to many laypeople. Of course, I'm a private pilot, so the potential interference to radio communications, GPS, etc maybe makes me a little more aware of it than most, but it's not like this is a new phenomenon or something we've just now discovered thanks to modern science. Humanity knew about these before the 1800's, and their effects on electrical devices were pretty clearly demonstrated by Mother Nature since at least 1859 (the Carrington Event, http://en.wikipedia.org/wiki/Solar_storm_of_1859 [wikipedia.org] ).

We've been hit by CMEs in the past, and their effects are pretty well understood. The potential impacts of this are real, and very inconvenient, in that they can knock out power grids with relative ease ( http://en.wikipedia.org/wiki/March_1989_geomagnetic_storm [wikipedia.org] ). We haven't had a strong hit since the cellular telephone was invented in 1989, so we have little experience with the really strong ones and modern electronics, but frying a few million computers and smartphones would (if not fatal) have some pretty nasty economic consequences for the owners of same.

The only level of lethality would be if you are somehow dependent on electricity, or the possible introduction of electricity into places you weren't expecting it. So, for example, if you hear about a strong geomagnetic event, it's probably not a good idea to go out and lean on any local ungrounded aluminum-sided house or any very large piece of ungrounded conductive material. You might become the grounding strap. That could be bad. Think of it as a lightning event, except it's smaller lightning but appears everywhere, even inside things.

Upside: While it's dark at night what with all the lack of power and your neighbors not burning their 10,000 watt back yard lights all night, you'll see the coolest aurora display ever if you live far enough north (and that could be as far south as Texas with a strong event). "Aurora Borealis, shinin' down in Dallas, can you picture that?"

We know it damages things as crude as telegraph machines, including setting the paper in them on fire from sparks, because it has. CMEs can impart energy into metal, and the electrical network is a huge freaking CME antenna, so in a strong storm expect at least temporary loss of power, and longer if there's enough strength to overload transformers and the like.

The CME can either cancel out the existing electricity in the power grid, or it can add to it, depending on polarity. A modestly strong CME impact can actually impart electricity into unshielded electronics and fry them where they sit due to nothing more sophisticated than voltage overload, even if they are not plugged in (this is known as "geomagnetically-induced current").

No, we'd probably have enough warning to get some looting and pillaging in, even if the event was cataclysmic. Light takes about 8 minutes to get from the sun to earth. Plasma, not being quite as fast, takes slightly longer.

...so we have little experience with the really strong ones and modern electronics, but frying a few million computers and smartphones would (if not fatal) have some pretty nasty economic consequences for the owners of same.

We don't need such experience. We have physics, which tells us that even extremely severe geomagnetic storms won't affect such devices at all.

Except we have a lead time and electricity providers who are very interested in not losing their expensive transformers. The space agencies provide space weather warnings including CME warnings. If a very large CME is inbound most of the affected transformers are going to be disconnected.

Plus, with CMEs on the scale we have seen so far, large-scale generator damage would only occur in certain areas, not worldwide, allowing functioning generators to be imported to rebuild at least part of the network in much less than several months.

Note that the last severe geomagnetic storm that caused a lot of damage... cut off six million people in North America for about nine hours.

I really don't know where you get your "intel", but for the most part your very mislead into the effects.

CME and flares have 3 main effects.

In space the plasma(high energy charged particles) is effectively a very high dose of radiation to satellites. This can cause temporary, or even in extreme cases, permanent failure. The radiation damages microelectronics, and cause little currents that cause parasitic transistors to "latch on".

The radiation also affects the ionosphere. This can have a dramatic effect on radio wave propagation through and off this layer of the atmosphere and will strongly affect communications that depend on this layer. It can in fact improve performance of some long wave bands.

Finally we come to the fact that the CME is a plasma and has a magnetic field with it. This pushes the earths magnetic field and can cause induction effects on earth surface. This is the only thing that affects terrestrial equipment. The radiation does not penetrate the ~10 metric tons of atmosphere per m^2. However the shifting magnetic field could lead to locally higher levels of background radiation, this would be more prevalent around the poles where its higher anyway. Also note that much of the little stuff blamed on the 1989 event is dubious. Even the wiki citation about "microchips" leads to a story where 3 hard drives failed (This happened to our raid system last year, we didn't blame CME).

The earth magnetic field is quite weak so the induction only affects very large "loops", like a telegram network or a electrical grid. Small "loops" like microelectronics, Aluminum buildings, ungrounded "metal" etc don't notice anything. It is nothing like lightning. Long range communications is now done with fiber for the most part, so the "large loops" are only city wide now days, and are unlikely to be badly affected. But electrical grids are somewhat susceptible, there are massive loops 100 even 1000 of km across. The voltage induced is still quite low, but this can still produce a very large current. This current is typically DC compared to the normal AC load power. This can have a detrimental effect on transformers by pushing the magnetic core into saturation. This typically disrupts wave forms and causes a "short circuit" and breakers should trip in at that point without serious damage being done. This was the case for march 1998 event, power was restored within 9 hours. However one large transformer was damaged. But this kind of redundancy is built into most grids and this did not seriously affect electrical supply in Canada outside the immediate affects.

Just to get a feel for the kind of "volts" we are talking about. Even if the full magnetic flux "swing" at the north pole (about 60uT/m2) in 1sec will induce just 18mV on a 10m radius *wire* loop. In practice this is very unrealistic and true swings is orders of magnitude less. From your links a swing of only 1.6uT for the 1859 event or 37 times less and over longer time intervals, ie a loop need to have an area of 625000m2 to induce 1V if that swing takes 1 sec (typically it takes *much* longer). Note you can't "ground" this emf, this is not how induction works, so you can't be a grounding strap it you touch the loop.